| 1999 |
TIN2 was identified as a TRF1-interacting protein by interaction cloning; it interacts with TRF1 in vitro and in cells, co-localizes with TRF1 at nuclei and metaphase chromosomes, and an N-terminal truncation mutant of TIN2 causes telomere elongation in a telomerase-dependent manner, establishing TIN2 as a negative regulator of telomere length that mediates TRF1 function. |
Interaction cloning (yeast two-hybrid), in vitro binding assay, co-immunoprecipitation, co-localization by immunofluorescence, dominant-negative overexpression with telomere-length measurement |
Nature genetics |
High |
10581025
|
| 2004 |
TIN2 directly binds both TRF1 and TRF2 simultaneously, linking the TRF1 and TRF2 complexes; TIN2 depletion by siRNA reduces TRF2 and hRap1 at telomeres, demonstrating that TIN2 stabilizes TRF2 on telomeres. |
Mass spectrometry, co-immunoprecipitation, Far-Western assay, yeast two-hybrid, siRNA knockdown with immunofluorescence quantification, gel filtration |
The Journal of biological chemistry |
High |
15316005
|
| 2004 |
TIN2 forms a ternary complex with TRF1 and tankyrase 1, stabilizes their interaction, and protects TRF1 from poly(ADP-ribosyl)ation by tankyrase 1 in vitro without affecting tankyrase 1 automodification, thereby acting as a PARP modulator in the TRF1 complex to regulate telomere length. |
Co-immunoprecipitation (ternary complex), in vitro poly(ADP-ribosyl)ation assay, siRNA/shRNA knockdown with telomere-length measurement, PARP inhibitor rescue, dominant-negative overexpression |
Nature genetics |
High |
15133513
|
| 2004 |
TIN2 mediates functions of TRF2 at telomeres; TIN2 interacts with TRF2 in vitro and in cells, and TIN2 mutants defective in binding TRF1 or TRF2 induce a DNA damage response and destabilize both TRF1 and TRF2 at telomeres. |
In vitro binding assay, yeast two-hybrid, co-immunoprecipitation in mammalian cells, dominant-negative overexpression with immunofluorescence |
The Journal of biological chemistry |
High |
15292264
|
| 2004 |
TIN2 interacts with PIP1 (TPP1) and bridges TRF1 to POT1; PIP1 tethers POT1 to the TRF1/TIN2 complex, and shRNA-mediated reduction of PIP1 or POT1 causes telomere elongation, establishing the TRF1-TIN2-PIP1-POT1 pathway for cis-inhibition of telomerase. |
Mass spectrometry identification, co-immunoprecipitation, shRNA knockdown with telomere-length measurement |
Genes & development |
High |
15231715
|
| 2004 |
TIN2 is essential for early embryonic development through a telomerase-independent pathway; homozygous TIN2 gene knockout in mice causes early embryonic lethality that is not rescued by inactivation of the telomerase reverse transcriptase gene. |
Gene targeting (knockout mouse), genetic epistasis with TERT knockout |
Molecular and cellular biology |
High |
15254230
|
| 2003 |
TIN2 stimulates TRF1-mediated clustering/interactions between telomeric DNA tracts in vitro (5–10-fold enhancement), and a dominant-negative TIN2 mutant that elongates telomeres in vivo disrupts these clusters, suggesting TIN2 promotes a higher-order telomeric structure that restricts telomerase access. |
In vitro telomeric DNA probe-clustering assay with biotinylated probes and streptavidin-agarose, dominant-negative protein competition |
EMBO reports |
Medium |
12835755
|
| 2006 |
TIN2 and TPP1 are both required to bridge the TRF1 and TRF2 subcomplexes into the full six-protein shelterin/telosome complex; TPP1 stabilizes the TRF1-TIN2-TRF2 interaction, and TPP1 knockdown reduces TRF1 association with the TRF2 complex. |
Reconstitution of six-protein complex in vitro, co-immunoprecipitation, shRNA knockdown, overexpression |
Proceedings of the National Academy of Sciences of the United States of America |
High |
16880378
|
| 2008 |
TIN2 deletion in mouse cells causes loss of TPP1/POT1a from telomeres, accumulation of RPA, and ATR kinase activation, establishing TIN2's major role as stabilizing TPP1/POT1a on single-stranded telomeric DNA to exclude RPA and repress ATR signaling; TIN2 also has a minor contribution to ATM repression by TRF2. |
Conditional gene deletion (TIN2 knockout mouse cells), immunofluorescence for telomere localization of shelterin proteins and RPA, kinase signaling assays |
Molecular cell |
High |
22099311
|
| 2010 |
TIN2-anchored TPP1 is required for telomerase recruitment to telomeres in human cells; depletion of TIN2 or TPP1 by shRNA reduces telomerase association with telomeres as measured by FISH and ChIP, and the OB-fold of TPP1 is required for this recruitment. |
shRNA depletion, telomerase FISH, chromatin immunoprecipitation (ChIP), deletion mutagenesis of TPP1 OB-fold |
Molecular and cellular biology |
High |
20404094
|
| 2011 |
TIN2 stability is regulated by the E3 ubiquitin ligase Siah2: TIN2 binds Siah2, is ubiquitylated in vivo, and Siah2 directly ubiquitylates TIN2 in vitro using purified proteins; Siah2 depletion stabilizes TIN2 protein levels and Siah2 overexpression removes TIN2 from telomeres in a RING-domain-dependent manner. |
Co-immunoprecipitation, in vivo ubiquitylation assay, in vitro ubiquitylation assay with purified proteins, siRNA depletion, overexpression with immunofluorescence |
Molecular and cellular biology |
High |
22064479
|
| 2011 |
DC-associated TIN2 missense mutations (e.g., R282H) lead to accelerated telomere shortening in human cells without altering total telomerase activity, TIN2 localization, or telomere end-protection status; instead, DC mutations reduce TIN2's ability to associate with TERC and telomerase activity, impairing TPP1-dependent telomerase recruitment. |
Ectopic expression of DC mutant TIN2 in human cells, telomere-length measurement, co-immunoprecipitation with TERC/telomerase, telomere end-protection assays |
The Journal of biological chemistry |
Medium |
21536674
|
| 2012 |
TIN2 is posttranslationally processed and localizes to mitochondria in addition to telomeres; TPP1 interacts with the TIN2 N-terminus (which contains overlapping mitochondrial and telomeric targeting sequences) and controls TIN2 localization; mitochondria-localized TIN2 regulates oxidative phosphorylation and ROS production. |
Subcellular fractionation, immunofluorescence co-localization, RNAi knockdown with metabolic assays (glycolysis, oxygen consumption, ROS measurement), deletion/truncation mapping of targeting sequences |
Molecular cell |
Medium |
22885005
|
| 2013 |
TIN2 is phosphorylated at serines 295 and 330 during mitosis in human cells, mediated at least in part by the mitotic kinase RSK2, which phosphorylates TIN2 in vitro. |
Phosphoproteomic analysis, Phos-tag gel electrophoresis, phosphorylation-specific antibodies, RSK2 overexpression and kinase inhibitor treatment, in vitro kinase assay |
PloS one |
Medium |
23977114
|
| 2014 |
TIN2 is the sole link between TPP1/POT1 heterodimers and the shelterin complex; a TIN2 allele deficient for TPP1 binding (TIN2ΔTPP1) but retaining TRF1 and TRF2 binding fully phenocopies the POT1a/b knockout phenotype without additional phenotypes, establishing that no other shelterin component contributes to TPP1/POT1 recruitment. |
Gene targeting to introduce separation-of-function TIN2 allele (TIN2ΔTPP1), telomere protection assays, immunofluorescence, comparison with POT1a/b KO phenotype |
The Journal of biological chemistry |
High |
25056954
|
| 2014 |
TIN2 requires interaction with TRF1 for optimal loading onto telomeres; a TRF1-binding-deficient TIN2 allele (TIN2-L247E) fused to TRF2-interacting Rap1-RCT bypasses the TRF1-loading requirement and is fully functional for chromosome-end protection by TRF2 and TPP1/POT1, demonstrating that a TRF2-tethered TIN2/TPP1/POT1 complex is sufficient for telomere protection. |
Gene targeting with separation-of-function alleles, Rap1-RCT fusion bypass approach, telomere protection assays, immunofluorescence |
Molecular and cellular biology |
High |
24469404
|
| 2014 |
A TIN2 DC mutation (K280E equivalent in mouse) causes telomere shortening through both telomerase-dependent and telomerase-independent mechanisms; TIN2(+/DC) mTR−/− mice showed accelerated telomere shortening compared to TIN2(+/+) mTR−/− controls, and the DC allele induced a fragile telomere phenotype suggestive of replication problems. |
Gene targeting to knock in DC allele in mice, intercrossing with mTR−/− mice (genetic epistasis), telomere FISH, ATR signaling assays, fragile telomere scoring |
Genes & development |
High |
24449270
|
| 2015 |
The TIN2-R282H DC mutation reduces the frequency of telomerase elongation at individual telomeres without disrupting shelterin occupancy, telomere damage signaling, or end protection, establishing a direct role for TIN2 in telomerase recruitment separable from its telomere-protection function. |
CRISPR/knock-in of TIN2-R282H in human cells, single-telomere extension assay (STELA-related), telomerase-telomere co-localization, DNA damage marker analysis |
PLoS genetics |
High |
26230315
|
| 2017 |
Crystal structure of the N-terminal domain of TIN2 in complex with TIN2-binding motifs from TPP1 and TRF2 reveals that TIN2 contains a TRFH-like domain that functions as a protein-protein interaction platform and that TIN2 interacts cooperatively with TPP1 and TRF2; structure-based mutagenesis confirmed the functional importance of these interfaces for stable shelterin assembly and telomere end protection. |
X-ray crystallography, structure-based mutagenesis, co-immunoprecipitation validation of mutant interactions, telomere protection assays |
Cell research |
High |
29160297
|
| 2018 |
TIN2L (long isoform), but not TIN2S, is phosphorylated, and this phosphorylation promotes enhanced interaction with TRF2; the DC cluster region in TIN2L further enhances TRF2 interaction. TRF2-F120 mediates TIN2L-specific interaction. TRF1 interacts more with TIN2S than TIN2L. Cells overexpressing TIN2L or phosphomimetic TIN2L permit telomere elongation, while TIN2S or phosphodead TIN2L do not. |
Co-immunoprecipitation of isoform-specific interactions, phosphorylation-specific antibodies, CRISPR/Cas9 elimination of TIN2L, overexpression of phosphomimetic/phosphodead mutants, telomere-length measurement |
Molecular and cellular biology |
Medium |
29581185
|
| 2018 |
Loss of the RNA-binding protein HuR during replicative senescence increases TIN2 protein levels by destabilizing TIN2 mRNA and reducing its translation; elevated TIN2 enhances mitochondrial localization of TIN2, increases ROS production, and contributes to cellular senescence induction and maintenance. |
RIP (RNA immunoprecipitation) of HuR-TIN2 mRNA interaction, HuR depletion with ROS and mitochondrial localization readouts, SA-β-gal senescence assays |
Nucleic acids research |
Medium |
29584879
|
| 2019 |
TIN2 (all three isoforms including newly identified TIN2M) stimulates telomerase processivity in vitro; this stimulation requires the TPP1 TEL patch, establishing that TIN2 functions together with TPP1/POT1 as a functional shelterin subcomplex to stimulate telomerase. |
Direct telomerase activity assay in vitro, identification of TIN2M isoform by cDNA cloning, immunofluorescence localization, TPP1 TEL-patch mutagenesis |
Molecular and cellular biology |
High |
31383750
|
| 2019 |
At the single-molecule level, TRF1 can substitute for TRF2 on TIN2 when TPP1 is absent; upon TPP1 binding, TIN2 binding capacity expands to simultaneously accommodate both TRF1 and TRF2, providing a mechanism for TPP1-driven stable TRF1-TIN2-TRF2 core complex formation. |
Fluorescence cross-correlation spectroscopy (FCCS) of single molecules in solution, reconstitution of TRF1-TIN2-TRF2 and TPP1-containing complexes |
Journal of molecular biology |
Medium |
31158366
|
| 2020 |
TINF2 is haploinsufficient for telomere length control; heterozygous deletion or truncating knock-in mutations of TINF2 result in excessive telomere elongation in clonal lines while telomere protection and genome stability are maintained, establishing TINF2 as a haploinsufficient tumor suppressor that limits telomere length. |
Heterozygous knock-in of truncating mutations by gene targeting, clonal analysis of telomere length, TINF2 heterozygous deletion, telomere protection assays |
eLife |
High |
33258446
|
| 2021 |
TIN2S and TIN2L isoforms facilitate TRF2-mediated telomeric DNA compaction (cis-interactions) and dsDNA-dsDNA, dsDNA-ssDNA, and dsDNA-ssRNA bridging (trans-interactions); TIN2 also facilitates TRF2-mediated T-loop formation, functioning as an architectural protein for higher-order telomeric nucleic acid structures. |
Single-molecule fluorescence imaging of DNA compaction, atomic force microscopy (AFM), DNA tightrope assay, reconstitution with purified TRF2 and TIN2 isoforms |
Nucleic acids research |
High |
34883513
|
| 2021 |
TIN2 short and long isoforms facilitate TRF1-mediated telomeric DNA compaction (cis-interactions) and DNA-DNA bridging (trans-interactions) in a telomeric sequence- and length-dependent manner; Tankyrase 1 + NAD+ reduces TRF1-TIN2-mediated bridging, while TIN2 protects against Tankyrase-induced disassembly; TPP1 inhibits TRF1-TIN2L-mediated DNA-DNA bridging. |
Atomic force microscopy (AFM), total internal reflection fluorescence microscopy (TIRFM), DNA tightrope assay, reconstitution with purified proteins |
The Journal of biological chemistry |
High |
34403696
|
| 2022 |
Introducing TIN2-DC mutations (T284R) in human embryonic stem cells (hESCs) causes short-telomere phenotype without triggering telomere DNA damage responses; frameshift mutation at exon 2 of TINF2 disrupts the mutant allele and restores telomere length, validating a gene-editing therapeutic strategy. |
CRISPR knock-in of DC mutations in hESCs and HSPCs, telomere-length measurement, DNA damage response assays, gene editing at exon 2 |
Blood |
Medium |
35421215
|
| 2022 |
TIN2 deficiency (homozygous Tin2S341X) in mouse embryonic stem cells causes ALT-associated phenotypes (excessively long heterogeneous telomeres, increased ALT-PML bodies, unstable chromosome ends), elevated Zscan4, and increased DAXX/ATRX and H3K9me3 at telomeres; mutant mESCs are impaired in differentiation, and differentiated cells show elevated telomeric DNA damage. |
Gene targeting in mESCs (homozygous truncation allele), ALT marker assays (FISH, CO-FISH, PML body immunofluorescence), ChIP for DAXX/ATRX/H3K9me3, differentiation assays |
Stem cell reports |
Medium |
35395177
|
| 2023 |
ATR-mediated phosphorylation of TRF2 at S410 stimulates TRF2 interaction with TIN2 both in vitro and at telomeres; PPM1D phosphatase dephosphorylates TRF2-S410 and its inhibition increases TIN2 and TPP1 occupancy at telomeres, while PPM1D overexpression reduces TIN2 and TPP1 at telomeres. |
Proximity biotinylation proteomics, co-immunoprecipitation, confocal microscopy, in vitro binding assay with phosphorylated TRF2, PPM1D inhibition/overexpression with chromatin immunoprecipitation readouts |
Nucleic acids research |
Medium |
36651296
|
| 2024 |
Mitochondria-localized TIN2 promotes phosphorylation of FOXO1 and its translocation to mitochondria; mitochondrial FOXO1 binds the D-loop region of mitochondrial DNA to inhibit mitochondrial respiration and is sequestered from nuclear target genes, weakening antioxidant defense and inducing RPE cell apoptosis under hyperglycemia. |
Co-immunoprecipitation, immunofluorescence, mitochondrial fractionation, ChIP for FOXO1 at mtDNA D-loop, TIN2 knockdown/overexpression with metabolic and apoptosis readouts |
Cell death and differentiation |
Medium |
39080375
|
| 2025 |
Fragment screening (X-ray crystallography and NMR) identified first-in-class inhibitors of the TRF1:TIN2 protein-protein interaction; compound 40 binds TRF1TRFH at the TIN2 interface (KD 29 µM), displaces a TIN2-TBM peptide probe (IC50 67 µM), and expels TRF1 from purified shelterin complex, structurally characterizing a hotspot at the TRF1:TIN2 interface. |
X-ray crystallography (XChem fragment screening), ligand-observed NMR, fluorescence polarization displacement assay, shelterin complex dissociation assay with purified proteins |
Scientific reports |
High |
41266376
|
| 2005 |
During growth arrest of human mammary epithelial cells, TIN2 reorganizes into one to three large nuclear subdomains that do not contain telomeres; expression of truncated TIN2 forms simultaneously prevents these domain formations and relaxes morphogenesis-induced growth arrest, indicating an extra-telomeric role for TIN2 in controlling cell proliferation. |
Immunofluorescence with telomere FISH (co-localization analysis), truncated TIN2 overexpression with proliferation/morphogenesis assays, DNase/RNase sensitivity |
Journal of cell science |
Medium |
15741234
|
| 2009 |
A TIN2 isoform (TIN2L) containing an additional 97 amino acids associates strongly with the nuclear matrix and cannot be extracted by stringent salt and detergent conditions, unlike TIN2S; in mammary epithelial cells, each isoform shows a distinct nuclear distribution as a function of cell cycle position and telomere length. |
Nuclear matrix fractionation with salt/detergent extraction, immunofluorescence, isoform-specific antibodies, cell cycle analysis |
Cell cycle (Georgetown, Tex.) |
Medium |
19229133
|
| 2011 |
Two TIN2 subcomplexes with distinct functions exist in human cells; a TIN2 mutant unable to bind TRF2 (TIN2-15C) is more potent than one unable to bind TRF1 (TIN2-13) in causing telomere uncapping and growth arrest in p53-competent cells, or cell death in p53-deficient cells. |
Biochemical isolation of TIN2 subcomplexes from nuclear lysates, TIN2 mutant overexpression, telomere uncapping assays, cell survival assays |
The Journal of cell biology |
Medium |
18443218
|